Difference between revisions of "Summer of Code - Getting Started"

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== ode15{i,s} : Matlab Compatible DAE solvers ==
 
== ode15{i,s} : Matlab Compatible DAE solvers ==
  
An initial implementation of a Matlab compatible ode15{i,s} solver,
+
An initial implementation of Matlab compatible Differential Algebraic Equations (DAE) solvers, {{manual|ode15i}} and {{manual|ode15s}}, based on [https://computing.llnl.gov/projects/sundials SUNDIALS],  
based on [http://computation.llnl.gov/projects/sundials SUNDIALS],  
+
was done by [https://gsoc2016ode15s.blogspot.com/ Francesco Faccio during GSoC 2016]. The code is maintained in the main Octave repository and consists mainly of the following three files: [https://hg.savannah.gnu.org/hgweb/octave/file/tip/libinterp/dldfcn/__ode15__.cc {{path|libinterp/dldfcn/__ode15__.cc}}], [https://hg.savannah.gnu.org/hgweb/octave/file/tip/scripts/ode/ode15i.m {{path|scripts/ode/ode15i.m}}] and [https://hg.savannah.gnu.org/hgweb/octave/file/tip/scripts/ode/ode15s.m {{path|scripts/ode/ode15s.m}}].
was done by Francesco Faccio during GSOC 2016.
 
The blog describing the work is [http://gsoc2016ode15s.blogspot.it/ here].
 
The resulting code has been pushed into the main Octave repository in the development branch and
 
consists mainly of the following three files
 
[https://hg.savannah.gnu.org/hgweb/octave/file/tip/libinterp/dldfcn/__ode15__.cc __ode15__.cc],
 
[https://hg.savannah.gnu.org/hgweb/octave/file/tip/scripts/ode/ode15i.m ode15i.m] and
 
[https://hg.savannah.gnu.org/hgweb/octave/file/tip/scripts/ode/ode15s.m ode15s.m].
 
The list of outstanding tracker tickets concerning this implementation can be found
 
[https://savannah.gnu.org/search/?Search=Search&words=ode15&type_of_search=bugs&only_group_id=1925&exact=1&max_rows=25#options here]
 
  
Possible useful improvements that could be done in a new project include:
+
The {{manual|decic}} function for selecting consistent initial conditions for ode15i can be made more Matlab compatible by using [https://faculty.smu.edu/shampine/cic.pdf another algorithm].  Another useful extension is to make ode15{i,s} work with datatypes other than double and to improve interpolation at intermediate time steps.
  
* Implement a better function for selecting consistent initial conditions compatible with Matlab's decic.m. The algorithm to use is described [http://faculty.smu.edu/shampine/cic.pdf here]
 
* make ode15{i,s} work with datatypes other than double
 
* improve interpolation at intermediate time steps.
 
* general code profiling and optimization
 
 
Other tasks, not strictly connected to ode15{i,s} but closely related, that could be added
 
to a possible project plan would be improving documentation and tests in odepkg and removing
 
overlaps with the documentation in core Octave.
 
 
 
* '''Required skills'''
 
* '''Required skills'''
 
: Knowledge of Octave, C/C++; familiarity with numerical methods for DAEs
 
: Knowledge of Octave, C/C++; familiarity with numerical methods for DAEs

Revision as of 01:02, 21 January 2021

Since 2011 the GNU Octave project has mentored 38 students in Summer of Code (SoC) programs by Google and ESA. Those programs aim to populate open-source software development and to attract potential new Octave developers.

Steps toward a successful application

  1. 😉💬 We want to get to know you. Communicate with us.
    • Join Octave Discourse or our IRC channel.
    • We are interested in you as motivated developer 💻 There is no need to present an overwhelming CV with prestigious universities 🏰 and programming contest awards 🏆 in it. We are very fine if you just communicate using a nickname with us.
    • If your first question is "Hi I'm new to Octave. What should I do?" you are out 🤦
    • Remember, we are mentors and not your boss 🙂
  2. 📝💡 Tell us what you are going to do.
    • When you contact us for the first time, do not write just to say in what project you're interested in. Be specific about what you are going to do, post many links 🔗, show us you know what you are talking about 💡, and ask many smart questions 🤓
  3. 👩‍🔬 Get your hands dirty.
    • We are curious about your programming skills ⌨️
    • Use Octave!
      • If you come across something that does not work the way you like ➡️ try to fix that 🔧
      • Or you come across a missing function ➡️ try to implement it.
  4. 📔 Prepare your proposal with us.
    • GSoC, for example, requires to submit a proposal.
    • If we see your proposal for the first time after the application deadline, you can easily imagine that it might contain ambiguities or some paragraphs are not fully clear to us. We easily get doubts if you are capable of working on your project 😓
    • Try to show us as early as possible a draft of your proposal 👍

How do we judge your application?

Depending on the mentors and SoC program there are varieties, but typically the main factors considered would be:

  • You have demonstrated interest in Octave and an ability to make substantial modifications to Octave
    The most important thing is that you've contributed some interesting code samples to judge your skills. It's OK during the application period to ask for help on how to format these code samples, which normally are Mercurial patches.
  • You showed understanding of your topic
    Your proposal should make it clear that you're reasonably well versed in the subject area and won't need all summer just to read up on it.
  • Well thought out, adequately detailed, realistic project plan
    "I'm good at this, so trust me" isn't enough. In your proposal, you should describe which algorithms you'll use and how you'll integrate with existing Octave code. You should also prepare a project timeline and goals for the midterm and final evaluations.

What you should know about Octave

GNU Octave is mostly written in C++ and its own scripting language that is mostly compatible with Matlab. There are bits and pieces of Fortran, Perl, C, awk, and Unix shell scripts here and there. In addition to being familiar with C++ and Octave's scripting language, you as successful applicant will be familiar with or able to quickly learn about Octave's infrastructure. You can't spend the whole summer learning how to build Octave or prepare a changeset and still successfully complete your project 😇

You should know:

  1. How to build Octave from it's source code using the GNU build system.
  2. How to submit patches (changesets).

Suggested projects

The following suggested projects are distilled from the Projects page for the benefit of potential SoC students. You can also look at our completed past projects for more inspiration.

Info icon.svg
Do you use Octave at your university or do you have some numerical project in mind? You are always welcome to propose your own projects. If you are passionate about your project, it will be easy to find an Octave developer to mentor and guide you.

ode15{i,s} : Matlab Compatible DAE solvers

An initial implementation of Matlab compatible Differential Algebraic Equations (DAE) solvers, ode15i and ode15s, based on SUNDIALS, was done by Francesco Faccio during GSoC 2016. The code is maintained in the main Octave repository and consists mainly of the following three files: libinterp/dldfcn/__ode15__.cc, scripts/ode/ode15i.m and scripts/ode/ode15s.m.

The decic function for selecting consistent initial conditions for ode15i can be made more Matlab compatible by using another algorithm. Another useful extension is to make ode15{i,s} work with datatypes other than double and to improve interpolation at intermediate time steps.

  • Required skills
Knowledge of Octave, C/C++; familiarity with numerical methods for DAEs
  • Potential mentors
Francesco Faccio, Carlo de Falco, Marco Caliari, Jacopo Corno, Sebastian Schöps

Using Python within Octave

Pythonic allows one to call Python functions and interact with Python objects from within Octave .m file code and from the Octave command line interface. Pythonic may eventually not be a separate package, but rather a core feature of Octave. This project aims to improve Pythonic with the goal of making the package more stable, maintainable, and full-featured.

Based on a previous summer project related to Pythonic, this work will consist of fast-paced collaborative software development based on tackling the Pythonic issue list. You would also be expected to participate in software design decisions and discussion, as well as improve documentation, doctests, and unit tests. As an example of the sorts of decisions being made, note that Octave indexes from 1 whereas Python typically indexes from 0; in which cases is it appropriate to make this transparent to the user?

  • Required skills
Knowledge of Octave, C/C++, Python
  • Potential mentors
Mike Miller, Colin B. Macdonald, Abhinav Tripathi

Improve TIFF image support

Tag Image File Format (TIFF) is the de facto standard for scientific images. Octave uses the GraphicsMagic (GM) C++ library to handle TIFF and many others image formats. However, GM still has several limitations:

  • GM has build option quantum which defines the bitdepth to use when reading an image:
    • Building GM with high quantum means that images of smaller bitdepth will take a lot more memory when reading.
    • Building GM with low quantum will make it impossible to read images of higher bitdepth. It also means that the image needs to always be rescaled to the correct range.
  • GM supports unsigned integers only, thus incorrectly reading files such as TIFF with floating-point data.
  • GM hides details of the image such as whether the image file is indexed. This makes it hard to access the real data stored on file.

This project aims to implement better TIFF image support using libtiff, while leaving GM handle all other image formats. After writing a classdef interface to libtiff, improve the Octave functions imread, imwrite, and imfinfo to make use of it.

  • Required skills
Knowledge of Octave, C/C++
  • Potential mentors
Carnë Draug

PolarAxes and Plotting Improvements

Octave currently provides supports for polar axes by using a Cartesian 2-D axes and adding a significant number of properties and callback listeners to get things to work. What is needed is the implementation of a dedicated "polaraxes" object in C++. This will require creating a new fundamental graphics object type, and programming in C++/OpenGL to render the object. When "polaraxes" exists as an object type, then m-files will be written to access them, including polaraxes.m, polarplot.m, rticks.m, rticklabels.m, thetaticks, thetaticklabels.m, rlim.m, thetalim.m. This relates to bug #49804.

  • Required skills
Knowledge of Octave, C/C++; optional experience with OpenGL programming
  • Potential mentors
Rik

Adding functionality to packages

OCS package

The OCS package is a circuit simulator. The objective of this project is to increase compatibility with SPICE and improve compatibility with other Octave packages, e.g. the Control package. Please study the available functions of this package.

  • Required skills
Knowledge of Octave, C/C++; FORTRAN API knowledge
  • Potential mentors
Sebastian Schöps, Carlo de Falco

Symbolic package

The Symbolic package provides symbolic computing and other computer algebra system tools. The main component of Symbolic is a pure m-file class "@sym" which uses the Python package SymPy to do (most of) the actual computations. The package aims to expose the full functionality of SymPy while also providing a high level of compatibility with the Matlab Symbolic Math Toolbox. The Symbolic package requires communication between Octave and Python. In 2016 another GSoC project successfully re-implemented this communication using the new Pythonic package.

This project proposes to go further: instead of using Pythonic only for the communication layer, we'll use it throughout the Symbolic project. For example, we might make "@sym" a subclass of "@pyobject". We also could stop using the "python_cmd" interface and use Pythonic directly from methods. The main goal was already mentioned: to expose the full functionality of SymPy. For example, we would allow OO-style method calls such as f.diff(x) instead of diff(f, x).

  • Required skills
Knowledge of Octave, C/C++, Python; object-oriented programming (OOP) in Octave
  • Potential mentors
Colin B. Macdonald, Mike Miller, Abhinav Tripathi

TISEAN package

The TISEAN package provides an Octave interface to TISEAN is a suite of code for nonlinear time series analysis. In 2015, another GSoC project started with the work to create interfaces to many TISEAN functions, but there is still work left to do. There are missing functions to do computations on spike trains, to simulate autoregresive models, to create specialized plots, etc. Which are of importance for many scientific disciplines involving statistical computations and signal processing.

  • Required skills
Knowledge of Octave, C/C++; FORTRAN API knowledge
  • Potential mentors
KaKiLa